Encryption and decryption of transmitted data is necessary to ensure privacy against eavesdropping and to provide security against unwanted interception of the transmitted data. In the field of cryptography, data may be encrypted using mathematical algorithms such as DES (Data Encryption Standard), RSA (Rivest, Shamir, and Adleman) and DSA (Digital Signature Algorithm). Current technology may implement these algorithms using computers or specialized electronic circuitry. Once the data is encrypted, the information may be sent via wires, microwaves or fiber optics. However, the entire encryption process is dependent upon the data rate of the algorithms and the electronics used to implement the algorithms.
A major portion of the telecommunications industry is moving towards high data rate Dense Wavelength Division Multiplexing (“DWDM”) systems for transmitting large amounts of data over fiber optic transmission lines. DWDM systems give telecommunications providers the ability to provide multiple services on a single optical channel. This may be accomplished by transmitting many wavelengths of light simultaneously over a single optical channel. Multiple optical signals may be combined, amplified as a group and transmitted. Current systems are capable of concurrently transmitting more than 150 different wavelengths of light and have demonstrated a 640 Gigabit per second (“Gb/s”) DWDM test bed operating over 7,000 km of fiber using a 64-wavelength system operating at 10 Gb/s per channel. Ultra high-speed systems operating in excess of 20 Gb/s per channel are predicted for the near future. The current electronic encryption solutions are unable to cost-effectively encrypt data at these levels. In order to perform encryption and decryption at these data transmission speeds, the encryption and decryption must be performed directly on the optical data without the need for intervening electronics that would slow the process down. By performing the encryption and decryption directly on the optical data, the process becomes virtually independent of data rate.